Chapter 4 - Development

Question 0

gametes

Answer 0

sperm and secondary oocytes; produced by gonads (testes and ovaries)

Question 1

sexual reproduction

Answer 1

process by which organisms produce offspring

Question 2

developmental biology

Answer 2

study of the sequence of events from the fertilization of a secondary oocyte by a sperm cell to the formation of an adult organism

Question 3

embryonic period

Answer 3

fertilization to 8th week of development

Question 4

embryo

Answer 4

developing human

Question 5

embryology

Answer 5

study of development from fertilization to the 8th week

Question 6

fetal period

Answer 6

week 9 until birth

Question 7

fetus

Answer 7

developing human from week 9 until birth

Question 8

prenatal development

Answer 8

time from fertilization to birth and includes both embryonic period and fetal period. divided into 3 periods, trimesters

Question 9

first trimester

Answer 9

most critical stage of development; all major organ-systems begin to develop; embryo most vulnerable to the effects of drugs, radiation, and microbes.

Question 10

second trimester

Answer 10

characterized by the nearly complete development of organ-systems; at end of stage fetus assumes distinctly human features

Question 11

third trimester

Answer 11

rapid fetal growth in which the weight of the fetus doubles; during early stages most organ systems become fully functional

Question 12

ovaries

Answer 12

paired organs in the superior portion of the pelvic cavity on either side of the uterus;produce secondary oocytes and discharge them into the peritoneal cavity each month (ovulation)

Question 13

Fallopian tubes

Answer 13

extend laterally from uterus, path for embryo from peritoneal cavity

Question 14

uterus

Answer 14

inverted pear-shaped organ in the pelvic and lower abdominal cavity; consists of a superior portion (fundus), middle portion (body), and inferior portion (cervix)

Question 15

uterine cavity

Answer 15

interior body of uterus

Question 16

cervical canal

Answer 16

interior of cervix

Question 17

endometrium

Answer 17

vascular, glandular lining of uterus at menstration

Question 18

myometrium

Answer 18

largest mass of smooth muscle in body; underneath endometrium; responsible for strong contractions to expel endometrium.

Question 19

vagina

Answer 19

multi-purpose canal attached to cervix and open to the exterior

Question 20

fertilization

Answer 20

genetic material from aa haploid sperm cell and a haploid secondary oocyte merges into a single diploid nucleus

Question 21

capacitation

Answer 21

series of functional changes that cause the sperms tail to beat even more vigorously and prepare its plasma membrane to fuse with the oocytes plasma membrane.

Question 22

corona radiata

Answer 22

cells that surround the secondary oocyte

Question 23

zona pellucida

Answer 23

clear glycoprotein layer between the corona radiata and the oocytes plasma membrane

Question 24

acrosome

Answer 24

helmetlike structure that covers the head of the sperm, contains several enzymes

Question 25

acrosomal reaction

Answer 25

release of contents of the acrosome

Question 26

syngamy

Answer 26

fusion with the oocyte

Question 27

polyspermy

Answer 27

fertilization by more than one sperm cell

Question 28

path of sperm cell

Answer 28

corona radiata -> zona pellucida ->plasma membrane of secondary oocyte -> cytoplasm of secondary oocyte

Question 29

dizygotic (fraternal) twins

Answer 29

produced from the independent release of 2 secondary zygotes and the subsequent fertilization of them by 2 sperm

Question 30

monozygotic (identical) twins

Answer 30

develop from a single fertilized ovum; contain exact same genetic code; separation of zygote into 2 embryos, 99% of the time within 8 days of fertilization

Question 31

conjoined twins

Answer 31

often result of zygote separation after first 8 days of fertilization.; share some body structures

Question 32

ectopic pregnancy

Answer 32

occurs outside uterus, often in Fallopian tubes

Question 33

cleavage

Answer 33

zygote undergoes miotic cell division that initially increase the number of cells without increasing the overall size of the cell mass; first division begins ~24 hours after fertilization and ends 6 hours later

Question 34

blastomeres

Answer 34

progressively smaller cells produced by clevage

Question 35

morula

Answer 35

solid sphere of cells from clevage

Question 36

uterine milk

Answer 36

glycogen-rich secretion from the glands of the endometrium, passes into the uterine cavity and enters the morula through the zona pellucida

Question 37

blastocyst cavity

Answer 37

large fluid cavity collecting blastomeres

Question 38

blastocyst

Answer 38

day 5 after fertilization; hundreds of cells but same size as original zygote

Question 39

embryoblast

Answer 39

inner cell mass; located internally and eventually develops into the embryo and some of the extraembryonic membranes

Question 40

trophoblast

Answer 40

outer superficial layer of cells that forms the sphere like wal of the blastocyst

Question 41

placenta

Answer 41

site of exchange of nutrients and waste between mother and fetus

Question 42

implantation

Answer 42

6 days after fertilization the blastocyte loosely attaches to endometrium

Question 43

decidua

Answer 43

functional layer of the endometrium

Question 44

decidua basalis

Answer 44

portion of the endometrium beneath the implanting embryo; later becomes maternal part of the placenta

Question 45

decidula parietalis

Answer 45

the remaining modified endometrium that lines the noninvolved areas of the rest of the uterus

Question 46

decidua capsularis

Answer 46

the portion of the endometrium that will cover the embryo after it implants in the endometrium

Question 47

stem cells

Answer 47

unspecialized cells that have the ability to divide for undefined periods and give rise to specialized cells

Question 48

therapeutic cloning

Answer 48

envisioned as a procedure in which the genetic material of a patient with a particular disease is used to create pluripotent stem cells to treat the disease

Question 49

syncytiotrophoblast

Answer 49

2 layers in the region of contact b/w the blastocyst and endometrium; no distinct boundary

Question 50

cytotrophoblast

Answer 50

area b/w the embryoblast and syncytiotrophoblast that has distinct cell boundaries

Question 51

key hormone in maintenance of pregnancy

Answer 51

hCG